Changes in the innate immune response of Atlantic salmon, Salmo salar L., exposed to experimental infection with Neoparamoeba sp.

Abstract

An experiment was conducted to determine the effect of Neoparamoeba sp. infection on the innate immune responses of Atlantic salmon. Atlantic salmon were experimentally infected with Neoparamoeba sp. and serially sampled 0, 1, 4, 6, 8 and 11 days post-exposure (dpe). Histological analysis of infected fish gill arches identified the presence of characteristic amoebic gill disease lesions as early as 1 dpe with a steady increase in the number of affected gill filaments over time. Immune parameters investigated were anterior kidney phagocyte function (respiratory burst, chemotaxis and phagocytosis) and total plasma protein and lysozyme. In comparison with non-exposed control fish basal respiratory burst responses were suppressed at 8 and 11 dpe, while phorbol myristate acetate-stimulated activity was significantly suppressed at 11 dpe. Variable differences in phagocytic activity and phagocytic rate following infection were identified. There was an increase in the chemotactic response of anterior kidney macrophages isolated from exposed fish relative to control fish at 8 dpe. Total protein and lysozyme levels were not affected by Neoparamoeba sp. exposure.

Immune responses and protection in catla (Catla catla) vaccinated against epizootic ulcerative syndrome

“…An increase in the respiratory burst activity of Atlantic salmon was observed on 4th day after experimental infection with Neoparamoeba sp. followed by a decrease in the activity after 11th day [29]. Similar trend was also observed in rohu sensitized with A. hydrophila [20].…”

Immune responses and expression profiles of some immune-related genes in Indian major carp, Labeo rohita to Edwardsiella tarda infection

“…To understand the changes in the immune system, those occur during edwardsiellosis, it is necessary to evaluate various immune parameters during the infection period. Several authors have documented such changes in innate as well as specific immune parameters in fish exposed to other pathogens [10e12, 14,41]. However, the immunomodulation mechanism in fish induced by E. tarda is still poorly understood.…”

“…Similarly, Gross et al noticed suppression of basal respiratory burst responses in Atlantic salmon at 8 and 11 days post-exposure to one parasitic infection, Neoparamoeba sp[41].…”

Expression of natriuretic peptide receptor mRNA and functional response to atrial natriuretic peptide and C-type natriuretic peptide in rainbow trout (Oncorhynchus mykiss) head kidney leucocytes

“…The process of dissection took less than 10 min per fish. Cells were isolated on a discontinuous 34/51% Percoll gradient according to the method of Secombes [18] as modified by Gross [19]. The resultant leucocytes were either stored in RNAlaterä for mRNA isolation (see below).…”

“…The generation of O 2 À by leucocytes was determined in situ spectrophotometrically after 1 h incubation of the cells with the peptides, 8-bromo-cGMP or the GC inhibitor by the reduction of nitroblue tetrazolium (NBT) (SigmaeAldrich Pty Ltd) according to Secombes [18] as outlined by Gross [19] and the absorbance read at 620 nm using a Rainbow Thermo Spectra microtitre plate reader.…”